Default arguments transform is not equivalent

[osuushi]

Example:

function example (x) {
  x = x || 1;
  return x;
}

example(0); // --> 1

But the transformed version:

function example(x=1) {
  return x;
}

example(0); // --> 0

This same issue also applies to the transform for a = a ? a : 1

[nene]

That's true. That's one of the several corner cases where Lebab goes wrong. It's simply following heuristics, and these aren't 100% reliable.

We could exclude these two patterns from the transform, but that would make the transform pretty useless - while x = x || 1 is quite common pattern, x = x === undefined ? x : 1 is pretty rare one.

I guess the best I can do is to link this issue from the main page, similarly to #107, to make people more aware of the potential pitfalls.

[nene]

Thanks for bringing this up.

I've restructured README to emphasize which transforms are "safe" and which are "unsafe", like this default-param transform.